Medical device delivery member with flexible stretch resistant distal portion

ABSTRACT

A delivery member is provided for delivering and deploying an intravascular medical device. The delivery member includes a flexible distal portion including a wound wire coil surrounded by a flexible sleeve and inhibited from extending lengthwise by a stretch resistant member positioned through the lumen of the coil. The delivery member can include hypotubes positioned on either side (distally and proximally) from the wound wire coil to which the stretch resistant member and the wound wire coil can be attached. The distal hypotube can include attachment slots for positioning and attaching a loop wire to the distal hypotube.

FIELD OF INVENTION

This invention generally relates to intravascular medical device systemsthat navigable through body vessels of a human subject. Moreparticularly, this invention relates to delivery systems and deliverymembers for delivering and deploying an implantable medical device to atarget location of a body vessel and methods of using the same.

BACKGROUND

The use of catheter delivery systems for positioning and deployingtherapeutic devices, such as dilation balloons, stents and emboliccoils, in the vasculature of the human body has become a standardprocedure for treating endovascular diseases. It has been found thatsuch devices are particularly useful in treating areas where traditionaloperational procedures are impossible or pose a great risk to thepatient, for example in the treatment of aneurysms in cranial bloodvessels. Due to the delicate tissue surrounding cranial blood vessels,e.g. brain tissue, it can be difficult and often risky to performsurgical procedures to treat defects of the cranial blood vessels.Advancements in catheter-based implant delivery systems have provided analternative treatment in such cases. Some of the advantages of catheterdelivery systems are that they provide methods for treating bloodvessels by an approach that has been found to reduce the risk of traumato the surrounding tissue, and they also allow for treatment of bloodvessels that in the past would have been considered inoperable.

Typically, these procedures involve inserting a delivery catheter intothe vasculature of a patient and guiding it through the vasculature to apredetermined delivery site. A vascular occlusion device, such as anembolic coil, can be attached to an implant engagement/deployment system(referred to herein equivalently as an “engagement system” or“deployment system”) at a distal end of a delivery member (e.g.micro-catheter) which pushes the coil through the delivery catheter andout of the distal end of the delivery catheter into the delivery site.Example delivery members and engagement/deployment systems are describedin U.S. patent application Ser. Nos. 15/850,993, 15/964,857, and16/502,767, each of which are incorporated herein by reference.

Some of the challenges that have been associated with properly executingsuch treatment procedures include ensuring the delivery member andengagement system remain in a stable position throughout a treatment.For example, in some aneurysm treatment applications, as the aneurysmbecomes increasingly packed with embolic material, the delivery membercan tend to shift due to increasing pushback from the embolic materialbeing implanted. If the delivery member shifts during treatment, aphysician may not be able to accurately control placement of embolicmaterial and may choose to cease packing the aneurysm. In such anexample, the aneurysm may not be sufficiently packed, which can lead torecanalization. Further, excessive movement or stretching of thedelivery member and/or engagement system thereon can result in prematuredetachment of the embolic coil.

There is therefore a need for improved methods, devices, and systems toprovide an implant delivery member and implant engagement system withincreased stability.

SUMMARY

It is an object of the present invention to provide systems, devices,and methods to meet the above-stated needs. Generally, it is an objectof the present invention to provide a delivery member for delivering anddeploying an implantable medical device having a flexible distalportion.

Stiffness of the distal portion of the delivery member can cause themicrocatheter used for delivery of the embolic material to pull back outof the aneurysm as the distal end of the delivery member is advancedthrough the tortuous distal anatomy. If the microcatheter pulls backwhile advancing the embolic material, the microcatheter may come out ofthe aneurysm and the physician may lose control of the embolic coil andnot be able to accurately control placement of embolic material and maynot be able to complete treatment.

Flexibility can be provided by incorporating a length of wound coilalong the distal portion of the delivery member. The wound coil can beprotected by a flexible polymer sleeve positioned around the outside ofthe coil. The wound coil can be inhibited from elongating by a stretchresistant tube affixed to hypotubes on either end of the wound coil.

An example delivery member for delivering an implantable medical deviceto a target location of a body vessel can include a proximal hypotube, asupport coil section, a distal hypotube, and an engagement system. Thesupport coil section can be affixed to a distal end of the proximalhypotube. The distal hypotube, support coil section, and proximalhypotube can form a contiguous tubular structure having a lumentherethrough. The distal hypotube can include a distal end shaped toreceive the implantable medical device. The distal hypotube can includea first attachment slot that extends from the lumen to an outer surfaceof the distal hypotube. The distal hypotube can include a secondattachment slot that extends from the lumen to an outer surface of thedistal hypotube. The engagement system can move to engage and deploy theimplantable medical device. The engagement system can include a loopwire and a pull wire. The loop wire can extend through an opening in theimplantable medical device thereby engaging the engagement system to theimplantable medical device. The loop wire can have a first end and asecond end. The first end can extend at least partially through thefirst attachment slot; the second end can extend at least partiallythrough the second attachment slot. The pull wire can extend through thelumen and engage the loop wire, thereby engaging the engagement systemto the implantable medical device. The pull wire can be moveable toretract proximally to disengage the loop wire to deploy the implantablemedical device.

The first attachment slot can have a distal end and a proximal end. Theproximal end can have a first diameter and the distal end can have asecond diameter. The first diameter of the first attachment slot can belarger than the second diameter of the first attachment slot. Similarly,the second attachment slot can have a distal end and a proximal end. Theproximal end can have a first diameter and the distal end can have asecond diameter. The first diameter of the second attachment slot can belarger than the second diameter of the second attachment slot.

The delivery member can include a first attachment connecting the firstend of the loop wire to the first attachment slot and a secondattachment connecting the second end of the loop wire to the secondattachment slot.

The loop wire can be a metallic material, and the first attachmentand/or the second attachment can be a weld.

The first attachment and/or the second attachment can include an epoxy.

The first attachment can be a first knot in the loop wire having a knotdiameter approximately equal to the first diameter of the firstattachment slot. The second attachment can be a second knot in the loopwire having a diameter approximately equal to the first diameter of thesecond attachment slot.

The loop wire can be a polymer material.

The distal hypotube can include a spiral cut along a longitudinal axispassing through the lumen.

The first attachment slot can be at a position on the distal hypotubeopposite the second attachment slot along a diameter line passingthrough the longitudinal axis. The first attachment slot can bepositioned proximal to the second attachment slot at a distance equal toone-half of a pitch of the spiral cut.

The first attachment slot can be at a first position equidistant fromtwo adjacent cuts of the spiral cut. The second attachment slot can beat a second position equidistant from two adjacent cuts of the spiralcut.

The first attachment slot and the second attachment slot can beperpendicular to the longitudinal axis.

An example distal hypotube for a delivery member can have a distal endshaped to receive an implantable medical device. The distal hypotube canhave a lumen extending through the distal hypotube. The distal hypotubecan include a first attachment slot extending from the lumen to an outersurface of the distal hypotube. The distal hypotube can include a secondattachment slot extending from the lumen to the outer surface. Thedistal hypotube can have a loop wire. The loop wire can be attached at afirst end to the first attachment slot and attached at a second end tothe second attachment slot. The distal hypotube can have a spiral cut inthe outer surface. The spiral cut can be cut along a longitudinal axispassing through the lumen.

The first attachment slot can have a distal end and a proximal end. Theproximal end of the first attachment slot can have a larger diameterthan the distal end of the first attachment slot. The second attachmentslot can have a distal end and a proximal end. The proximal end of thesecond attachment slot can have a larger diameter than the distal end ofthe second attachment slot. The loop wire can be attached to the firstattachment slot via a first attachment. The loop wire can be attached tothe second attachment slot via a second attachment.

The loop wire can be a metallic material, and the first attachmentand/or the second attachment can be a weld.

The first attachment and/or the second attachment can include an epoxy.

The first attachment can be a first knot in the loop wire having a knotdiameter approximately equal to the first diameter of the firstattachment slot. The second attachment can be a second knot in the loopwire having a diameter approximately equal to the first diameter of thesecond attachment slot.

The first attachment slot can be at a position on the distal hypotubeopposite the second attachment slot along a diameter line passingthrough the longitudinal axis. The first attachment slot can bepositioned proximal to the second attachment slot at a distance equal toone-half of a pitch of the spiral cut.

An example method for attaching an implantable medical device on adelivery member includes providing the delivery member. The deliverymember can include a flexible distal hypotube. The method can includepassing a first end of a loop wire through a proximal end of a firstattachment slot of the flexible distal hypotube. The method can includepulling the first end of the loop wire from the proximal end of thefirst attachment slot toward a distal end of the first attachment slot,the distal end having a smaller diameter than the proximal end. Themethod can include attaching the loop wire to the first attachment slot.The method can include passing a second end of the loop wire through aproximal end of a second attachment slot of the flexible distalhypotube. The method can include pulling the second end of the loop wirefrom the proximal end of the second attachment slot toward a distal endof the second attachment slot, the distal end having a smaller diameterthan the proximal end. The method can include attaching the loop wire tothe second attachment slot.

Attaching the loop wire to the first attachment slot can include weldingthe loop wire within the first attachment slot.

The method can include tying a first knot in the first end of the loopwire prior to pulling the first end of the loop wire from the proximalend of the first attachment slot toward the distal end of the firstattachment slot. The method can include tying a second knot in thesecond end of the loop wire prior to pulling the second end of the loopwire from the proximal end of the second attachment slot toward thedistal end of the second attachment slot.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further aspects of this invention are further discussedwith reference to the following description in conjunction with theaccompanying drawings, in which like numerals indicate like structuralelements and features in various figures. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingprinciples of the invention. The figures depict one or moreimplementations of the inventive devices, by way of example only, not byway of limitation.

FIG. 1 is an illustration of a cross section of a delivery memberaccording to aspects of the present invention;

FIG. 2A is an illustration of a cross section of a flexible sleeveaccording to aspects of the present invention;

FIG. 2B is an illustration of a cross section of a stretch resistanttube according to aspects of the present invention;

FIG. 2C is an illustration of a cross section of a wire coil affixed toa distal hypotube and a proximal hypotube according to aspects of thepresent invention;

FIGS. 2D through 2H are illustrations of a distal hypotube with a firstand second attachments slot according to aspects of the presentinvention;

FIGS. 3A through 3D are illustrations of an engagement systemillustrating a sequence for deploying an implant according to aspects ofthe present invention;

FIG. 4 is a flow diagram illustrating a method for designing orconstructing a delivery member according to aspects of the presentinvention;

FIG. 5 is a flow diagram illustrating a method for using a deliverysystem including an example delivery member according to aspects of thepresent invention; and

FIG. 6 is a flow diagram illustrating a method for attaching animplantable medical device to a delivery member.

DETAILED DESCRIPTION

During an intravascular treatment, for instance, an aneurysm occlusiontreatment, lack of flexibility of a distal portion of a treatment devicedelivery member can cause the delivery member to pull back from thetreatment site or otherwise move out of position while an implant orother medical treatment device is being placed in an aneurysm or othertreatment site. A delivery member and engagement system having a moreflexible distal portion can therefore provide a stable system fordelivering medical devices in neurovascular anatomy in addition to otherapplications facing a similar challenge. Flexible structures, howevercan tend deform, extend, or expand when navigating tortuous anatomy.Deformation of the delivery member can inhibit the delivery member'sability to navigate to a treatment site and/or effectively deploy themedical device. Elongation of the delivery member can result inpremature deployment of the medical device.

An object of the present invention is to provide a delivery memberhaving a highly flexible distal portion that is stretch resistant andstructurally stable throughout delivery and deployment of a medicaltreatment device. For ease of discussion, medical treatment devices aregenerally referred to herein as an “implant” although, as will beappreciated and understood by a person of ordinary skill in the art,aspects of the present invention can be applied to deliver and deploymedical treatment devices that are not left implanted.

According to the present invention, in some examples, the highlyflexible distal portion of the delivery member can include a coiledwire, an outer sleeve, and an inner stretch resistant member. The coiledwire can be formed of a substantially linear wire that is wound in acoil shape and/or a hypotube that is laser cut in a spiral pattern. Ifthe coiled wire is formed from a laser cut hypotube, the spiral can beabsent interference cuts connecting windings in the coil so as toprovide a more flexible coil. The outer sleeve can inhibit the coiledwire from deforming radially and/or provide a smooth surface againstwhich vascular walls can slide during delivery of an implant. Thestretch resistant member can inhibit elongation of the coiled wireduring delivery of the implant. The combination of the coiled wire,outer sleeve, and stretch resistant member can therefore provide adistal portion of a delivery member having greater flexibility andgreater stability than at least some known delivery members.

Turning to the figures, as illustrated in FIG. 1, an example deliverymember 10 can include a proximal tube 100, a coiled section 200, adistal tube 300, a sleeve 500 surrounding the coiled section, and astretch resistant member 600 within the lumen of the coiled section 200.In this disclosure, the terms proximal tube and proximal hypotube can beused interchangeably; similarly, the terms distal tube and distalhypotube can be used interchangeably. The proximal tube 100 can extend amajority of the length of the delivery member 10 with the coiled section200 and distal tube 300 forming a length sufficient to absorb a majorityof push-back that can occur during placement of an implant at atreatment site. In some examples, the length can measure between about30 cm and about 50 cm, or more specifically, about 40 cm. The proximaltube 100 can have a distal end 104 that is connected to a proximal end202 of the coiled section 200, and the coiled section 200 can have adistal end 204 that is connected to a proximal end 302 of the distaltube 300. As will be described in greater detail herein, the distal tube300 can include a compressible portion 306. The compressible portion 306can be formed from a spiral cut 307 in the distal tube 300, a woundwire, spiral ribbon, or other arrangement allowing axial adjustmentaccording to the present invention. A loop wire 400, which can secure animplant or other medical treatment device to the delivery member 10, canbe placed within the lumen 308 of the distal tube 300. The compressibleportion 306 of the distal tube 300 can include attachment slots (e.g., afirst attachment slot 310 and a second attachment slot 316) enabling theloop wire 400 to pass through the distal tube 300 from the lumen 308 toan outer surface 309 of the distal hypotube.

FIG. 2A is a cross sectional view of the sleeve 500. FIG. 2B is a crosssectional view of the stretch resistant member 600. FIG. 2C is a crosssectional view of the assembled proximal tube 100, coiled section 200,and distal tube 300.

The coiled section 200 can be formed separately from the proximalhypotube 100 and/or the distal hypotube 300. The separately formedcoiled section 200 can be affixed with welds 712, 714 or otherappropriate attachment to the proximal tube 100 and/or the distal tube300. Alternatively, or additionally, at least a portion of the coiledsection can be formed from a spiral laser cut portion of a hypotube. Aseparately formed coiled section 200 can be made more flexible comparedto a spiral cut tube by selecting a wire with a particular cross section(e.g. circular) with a particular diameter D, or by selecting a wirewith material properties to increase flexibility. Conversely, a lasercut portion can be more easily fabricated by cutting a single hypotubeto form the proximal tube 100, coiled section 200, and distal hypotube300, reducing or eliminating welds 712, 714 or other attachments. Ineither case, the wire of the coil 200 can have a diameter D measuringwithin a range including about 0.8 mils and 5 mils (about 20 nm to about130 nm).

The coiled section can be formed primarily of a non-radiopaque materialsuch as steel and can include a radiopaque section 216 made of aradiopaque material such as platinum and/or tungsten. The radiopaquesection 216 can be positioned between a proximal, non-radiopaque sectionof the coil 212 and a distal, non-radiopaque section of the coil 214.The radiopaque section 216 can be positioned a predetermined distancefrom a distal end 304 of the delivery member 10 so that a physician canreadily visualize the placement of the distal portion of the deliverymember during a treatment procedure. The proximal section 212,radiopaque section 216, and distal section 214 can be concentricallywelded.

The coiled section 200 can be surrounded by a flexible sleeve or fusedjacket 500, referred generically herein as a “sleeve.” The sleeve 500can inhibit the coil 200 from expanding radially and/or from engagingvascular walls during navigation. The sleeve 500 can include a polymer.The polymer can include additives to increase the lubricity of thesleeve 500 so that the sleeve can easily slide through a body vessel. Asillustrated in FIG. 2A, the sleeve 500 can have a wall thickness Tmeasuring within a range including about 0.5 mils and about 2 mils(about 0.01 mm to about 0.05 mm). The sleeve 500 can further be coatedwith a hydrophilic coating to further minimize friction duringintravascular navigation. The sleeve 500 can be fused or glued to thecoil 200, the proximal hypotube 100, and/or the distal hypotube 300.

The stretch resistant member 600 can be positioned to inhibit elongationof the coil 200 during intravascular navigation. The stretch resistantmember 600 can include a tube sized to fit within the lumen 208 of thecoil 200. The stretch resistant tube 600 can also be sized to extendthrough the entirety of the length of the coil 200, extend with a lumen108 of the proximal tube 100 and within the lumen 308 of the distal tube300. The stretch resistant member 600 can be attached to the proximaltube 100 and the distal tube 300 at adhesive joints 702, 704 or otherappropriate attachment. The stretch resistant member 600 can remainunattached to the coiled section 200 such that the stretch resistantmember 600 and coiled section 200 are able to move independently fromeach other to some extent.

The delivery member 10 can include a mechanical engagement system forengaging a medical device 12 during delivery to a treatment site, andthe delivery member 10 can be actuated mechanically to deploy themedical device 12. Mechanically actuated engagement systems can includeone or more inner elongated members or pull wires extending through thedelivery member that can be manipulated at the proximal end by aphysician to deploy a medical treatment device. Such a wire or innerelongated member is referred to herein generically as a “pull wire.”When reference is made herein to an engagement system, the engagementsystem can include the combination of a loop wire 400 and a pull wire140.

FIGS. 2D through 2H illustrate an example distal hypotube 300 that canbe used to secure a loop wire 400. The loop wire 400 can be positionedto secure an implant or other medical treatment device to the deliverymember 10 and can be moved to release the medical device 12 from theimplant or other medical treatment device. This convention will bedescribed in greater detail below in reference to FIGS. 3A-3D. Tosummarize, the loop wire 400 can extend over a locking portion 18 of amedical device 12. A pull wire 140 can then be slid through an opening405 at the distal end 404 of the loop wire 400. This can hold themedical device 12 in place until the pull wire 140 is retracted torelease the medical device 12.

FIG. 2D is a side view of a distal hypotube 300 with a first attachmentslot 310 and a second attachment slot 316 (the second attachment slot316 is in the background of the figure). The attachment slots 310, 316can be openings in the outer surface 309 of the distal hypotube 300 thatextend from the lumen 308 to the outer surface 309. The attachment slots310, 316 can facilitate attaching the loop wire 400 to the distalhypotube 300. The attachment slots 310, 316 can be laser cut, forexample, into the outer surface 309 of the distal hypotube 300.

The first attachment slot 310 can have a distal end 312 and a proximalend 314. As can be seen, a diameter 313 of the distal end 312 can besmaller than a diameter 315 of the proximal end 314 of the firstattachment slot 310. This tapered design can facilitate the attachmentof the loop wire 400 to the distal hypotube 300. For example, if theproximal end 314 is larger in diameter, the loop wire 400 can be fedthrough more easily. Once through the larger proximal diameter 315, theloop wire 400 can be pulled toward the distal end (312) of the firstattachment slot (310). In some examples, the transition between theproximal end 314 and the distal end 312 can be slightly tapered suchthat, as the loop wire 400 is pulled toward the distal end 312, the loopwire 400 can be wedged within the first attachment slot. The secondattachment slot 316 can be similar in all regards to the firstattachment slot 310. For example, the second attachment slot 316 canhave a distal end 322 and a proximal end 324, and a diameter 323 of thedistal end 322 can be smaller than a diameter 325 of the proximal end324 of the second attachment slot 316.

When the loop wire 400 is fed through the attachment slot 310, 316, andpulled toward the distal end 312, 322, the loop wire 400 can be attachedto the distal hypotube 300 via an attachment 409, 409. FIG. 2E depictsan example first attachment 408 (the second attachment 409 is in thebackground of this figure). Using the first attachment slot 310 as anexample (the second attachment slot 316 can be similar), the loop wire400 can be pulled toward the distal end 312 and positioned within thefirst attachment slot 310 at a desired location within the length of thefirst attachment slot 310. The loop wire 400 can then be attached to thefirst attachment slot 310 at a first attachment 408. The firstattachment 408 and/or the second attachment 409 can be disposed at thedistal end of their respective attachment slot 310, 316. It is notnecessary, however, that the first attachment 408 and/or the secondattachment 409 be disposed at the most distal end of the slots; thefirst attachment 408 and/or the second attachment 409 can be placed at amiddle section of the slot (i.e., more proximal), as shown in FIG. 2E.

The first attachment 408 can be a weld that holds the loop wire 400 tothe first attachment slot 310. In some examples, the loop wire 400 cancomprise metallic materials, such as stainless steel, cobalt-chromealloy, titanium, nickel-titanium alloy (nitinol), and the like.Similarly, the distal hypotube can comprise metallic materials, such asstainless steel, cobalt-chrome alloy, titanium, nitinol, and the like.This can enable the first attachment 408 to be a metallic weld attachingthe loop wire 400 to the first attachment slot 310. In some examples,the loop wire 400 can comprise a polymer material, such as nylon,polypropylene, silk, polyester, and the like. The loop wire can includebraided or monofilament wires. The first attachment 408 can be athermoplastic weld at the first attachment slot 310.

Additionally, or alternatively, the first attachment 408 can be an epoxyholding the end of the loop wire 400 to the first attachment slot 408.As stated above, the second attachment slot 316 can include a secondattachment 409 to attach the loop wire 400 to the second attachment slot316. The second attachment 409 can be similar to the first attachment408.

In some examples, the first attachment 408 can be a knot in the loopwire 400. As described above, the first attachment slot 310 can have aproximal end 314 that is larger in diameter than the distal end 312. Theloop wire 400 can be pulled through the first attachment slot 310, tiedinto a knot, and then pulled toward the distal end 312. The knot can belarger than the distal diameter 313 so that the loop wire 400 cannot bepulled back through the first attachment slot 310 once a knot is tied inthe loop wire 400. In other examples, the loop wire 400 can be tied intoa knot first, then the knot can be fed through the proximal end of 314of the first attachment slot 310, and then the loop wire 400 can bepulled toward the distal end 312. In these examples, a knot diameter canbe approximately equal to the first diameter 315 of the first attachmentslot 310. This would enable the loop wire 400 to be fed through theproximal end 314 but prohibit the loop wire 400 from being pulledthrough the distal end 312 of the first attachment slot 310. The secondattachment 409 can similarly be a knot in the opposite end of the loopwire 400.

FIG. 2F is a side view of an example distal hypotube 300. The firstattachment slot 310 is in the foreground of this figure; the secondattachment slot 316 is in the background. As described above, a distalhypotube 300 can have a flexible and/or compressible portion 306. Thecompressible portion 306 can be formed from a spiral cut 307 in thedistal hypotube 300, a wound wire, spiral ribbon, or other arrangementallowing axial adjustment according to the present invention. In someexamples, the placement of the first attachment slot 310 and/or thesecond attachment slot 316 can be selected based on a pitch of thespiral cut 307. To improve the flexibility of the distal hypotube 300,for example, the first attachment slot 310 can be offset from the secondattachment slot 316 by a ratio of the pitch of the spiral cut 307, asshown by slot offset 320. As shown in the figure, an example of thisslot offset 320 is that the first attachment slot 310 can be positionedopposite the second attachment slot 316, and the first attachment slot310 can be offset proximal to the second attachment slot 316 at adistance approximately equal to half of the pitch 318 of the spiral cut307. It is not necessary, however, that the first attachment slot 310 bepositioned opposite the second attachment slot 316. The first attachmentslot 310 can be disposed at a first position equidistant from twoadjacent cuts of the spiral cut 307, and the second attachment slot 316can disposed at a second position equidistant from two adjacent cuts ofthe spiral cut 307. This can be true for any position on the distalhypotube 300, whether or not the attachment slots 310, 316 are oppositefrom each other on the other surface 309.

FIG. 2G is a perspective view of a distal hypotube 300 showing theexample offsetting of the first attachment slot 310 and secondattachment slot 316. Offsetting the first attachment slot 310 and thesecond attachment slot 316 with respect to the pitch of the spiral cut307 can increase the flexibility of the distal hypotube 300 by notimpeding its flexing about the spiral cut 307.

FIG. 2H is a side cross-sectional view of an example distal hypotube300. In some examples, the first attachment slot 310 and the secondattachment slot 316 can be formed (for example laser cut, drilled, etc.)into the distal hypotube 300 perpendicular to a longitudinal plane 326 bpassing through the lumen 308 of the distal hypotube 300. Thelongitudinal plane 326 b is the three-dimensional view of thelongitudinal axis 326 b passing through the lumen 308. Perpendicularcuts can help facilitate the attachment of the loop wire 400 to thefirst attachment slot 310 and the second attachment slot 316. Forexample, once the loop wire 400 is fed through the first attachment slot310 and the second attachment slot 316, perpendicular cuts can helpensure uniform surface contact between the loop wire 400 and the outerwalls of the attachment slots 310, 316.

FIG. 2H also provides a good view of an example slot offset 320 betweenthe first attachment slot 310 and the second attachment slot 316. Asdescribed above, a first attachment slot 310 can be disposed at aposition on the distal hypotube 300 opposite the second attachment slot316 along a diameter line passing through the longitudinal axis 326 a.The first attachment slot 310 and the second attachment slot 316 can beoffset based on the pitch of the spiral cut 307.

FIGS. 3A through 3D illustrate the delivery member 10 including amechanical engagement system including a pull wire 140 and a loop wire400 that can be positioned to secure an implant or other medicaltreatment device to the delivery member 10 and can be moved to releasethe medical treatment device from the delivery member 10. The loop wire400 can be affixed to the distal tube 300 with first attachment 408 anda second attachment 409. The stretch resistant member 600 can be sizedto allow a pull wire 140 to pass through the lumens 108, 208, 308 of theproximal tube 100, coiled section 200, and distal tube 300. Forinstance, the stretch resistant member 600 can be tubular, having alumen therethrough, and the pull wire 140 can extend through the lumenof the tubular stretch resistant member 600. During manufacture of thestretch resistant member 600, the stretch resistant member 600 can beextruded over the pull wire 140.

The combination of the coil 200, sleeve 500, and stretch resistantmember 600 can provide a highly flexible distal portion of a deliverymember 10 suitable for navigating tortuous anatomy, includingneurovascular blood vessels. The stretch resistant member 600 cansupport the coil 200 to prevent the coil 200 from significantlyextending during navigation of a blood vessel, thereby reducing tensionon a pull wire 140 extending therethrough and reducing the likelihood ofpremature deployment of an attached medical treatment device.

The proximal tube 100 can include a flexible section 106 having materialremoved to increase flexibility of the flexible section 106. Theflexible section 106 can be cut in a spiral pattern. The spiral patternof the flexible section 106 can lack interference cuts connectingwindings within the spiral. The stretch resistant member 600 can extendthrough the flexible section 106 and be attached to the proximal tube100 in the proximal direction from the flexible section 106. The stretchresistant member 600 can thereby inhibit elongation of the flexiblesection 106 of the proximal tube 100 and coiled section 200. The sleeve500 can cover at least a portion of the flexible section 106 to inhibitdeformation of the flexible section and/or reduce friction withvasculature and the flexible section 106 during intravascularnavigation. In some examples, the sleeve 500 can cover about 10 cm ofthe proximal tube 100 approximate and/or including the distal end 104 ofthe proximal tube 100.

The distal hypotube 300 can include a compressible portion 306. Thecompressible portion 306 can be axially adjustable between an elongatedcondition and a compressed condition. The distal hypotube 300 can alsobe flexible such that the distal hypotube 300 can provide a stablesystem for delivering medical devices in neurovascular anatomy. Thedistal hypotube 300 can include a spiral cut 307, formed by a lasercutting operation for example, to create the compressible and/orflexible construct. Additionally, or alternatively, the compressibleportion 306 can be formed of a wound wire, spiral ribbon, or otherarrangement allowing axial adjustment according to the presentinvention. Preferably, the compressible portion 306 is in the elongatedcondition at rest and automatically or resiliently returns to theelongated condition from a compressed condition, unless otherwiseconstrained.

FIGS. 3A-3D, illustrate the detachment of the medical device 12 using amechanical engagement/deployment system. FIG. 3A illustrates theengagement system 140, 400 locked into the locking portion 18 of themedical device 12. The compressible portion 306 of the distal tube 300can be compressed and the loop wire 400 opening 405 at a distal end 404of the loop wire 400 can be placed through the locking portion 18. Whenthe pull wire 140 is put through the opening 405 the medical device 12is now secure. FIG. 3B illustrates the pull wire 140 being drawnproximally to begin the release sequence for the medical device 12. FIG.3C illustrates the instant the pull wire 140 exits the opening 405 andis pulled free of the loop wire 400. The distal end 404 of the loop wire400 falls away and exits the locking portion 18. As can be seen, thereis now nothing holding the medical device 12 to the delivery member 10(e.g., the distal hypotube 300). FIG. 3D illustrates the end of therelease sequence. Here, the compressible portion 306 hasextended/returned to its original shape and “sprung” forward. An elasticforce E is imparted by the distal end 304 of the distal tube 300 to themedical device 12 to “push” it away to ensure a clean separation anddelivery of the medical device 12.

Illustrations in the above-described figures depict generally hollow ortubular structures 100, 200, 300, 500, 600 according to the presentinvention. When used herein, the terms “tubular” and “tube” are to beconstrued broadly and are not limited to a structure that is a rightcylinder or strictly circumferential in cross-section or of a uniformcross-section throughout its length. For example, the tubular structureor system is generally illustrated as a substantially right cylindricalstructure. However, the tubular system may have a tapered or curvedouter surface without departing from the scope of the present invention.

FIG. 4 is a flow diagram including method steps for constructing ordesigning a delivery member such as the example delivery membersdescribed herein. Referring to the method 800 outlined in FIG. 4, instep 810, a first hypotube, a second hypotube, a flexible sleeve, a wirecoil, and a stretch resistant member can be selected. The first hypotubecan be a proximal hypotube 100 as described herein or as would otherwisebe known to a person of ordinary skill in the art. The second hypotubecan be a distal hypotube 300 as described herein or as would otherwisebe known to a person of ordinary skill in the art. The flexible sleevecan be a sleeve or fused jacket 500 as described herein or as otherwiseknown to a person of ordinary skill in the art. The wire coil caninclude the support coil, coiled section 200 as described herein or asotherwise known to a person of ordinary skill in the art. The stretchresistant member can be a stretch resistant member 600 as describedherein or as otherwise known to a person of ordinary skill in the art.

In step 820, the stretch resistant member can be positioned in the lumenof the wire coil. In step 820, the stretch resistant member that ispositioned can be substantially tubular. In step 830, the firsthypotube, wire coil, and second hypotube can be attached to each other.In step 840, the stretch resistant member is attached to the firsthypotube and the second hypotube. The first hypotube, wire coil, andsecond hypotube can be attached as illustrated and described herein orby other means as would be understood by a person of ordinary skill inthe art. Steps 820, 830, and 840 need not be performed in that order andcan be performed simultaneously. For instance, the stretch resistantmember can be attached to one of the first and second hypotubes asindicated in step 840, then the hypotube to which the stretch resistantmember is attached can be attached to the wire coil as indicated in step830, then the stretch resistant member can be positioned through thewire coil as indicated in step 820, then the other of the hypotubes canbe attached to the wire coil as indicated in step 830, then the stretchresistant member can be attached to that other hypotube as indicated instep 840.

In step 850, the wire coil can be covered with the flexible sleeve. Theflexible sleeve can cover some or all of the outer surface of the wirecoil. Step 850 can also include the step of fusing the flexible sleeveto the wire coil and/or otherwise affixing the flexible sleeve to thedelivery member. If the second hypotube has a flexible section, in step850, the flexible sleeve can also be positioned to cover at least aportion of the flexible section.

In step 860, an implant can be detachably attached to the distal end ofthe first hypotube. In step 860, the implant can be attached bypositioning a loop wire within the first hypotube, positioning a pullwire to extend through the first hypotube, coiled wire, and secondhypotube, and securing the implant with the loop wire and the pull wire.The pull wire can be extended from the proximal end of the secondhypotube. If the first hypotube has a compressible portion, in step 860,the compressible portion can be compressed, and the implant can beattached to delivery member while the compressible portion iscompressed.

FIG. 5 is a flow diagram including method steps for administering anintravascular treatment using a system including a delivery member suchas the example delivery members described herein. Referring to themethod 900 outlined in FIG. 5, in step 910 a system having a distalhypotube, proximal hypotube, coiled section co-axially positioned inbetween the hypotubes, a flexible sleeve covering the coiled section, astretch resistant member positioned within the coiled section, and amedical treatment device attached to or near the distal hypotube can beselected. The system can be suitable for intravascular treatments suchas described and illustrated herein or as otherwise known to a person ofordinary skill in the art.

In step 920, the system can be moved through a catheter to a treatmentsite such as the site of an aneurysm or other abnormality in a bloodvessel. In step 930, the system can be flexed as it is moved through thecatheter. In step 940, the coiled section of the system can be preventedfrom deforming by the flexible sleeve and the stretch resistant member;the flexible sleeve can inhibit the coiled section from deformingradially while the stretch resistant member can inhibit the coil fromextending longitudinally.

In step 950, the medical treatment device can be deployed. In the casethat the medical treatment device is an implant, in step 950 the implantcan be detached. In step 960, the distal tube can extend to push themedical treatment device away from the distal tube. In the case that themedical treatment device is an implant detached in step 950, in step960, the detached implant can be ejected away from the distal tube inresponse to the expansion of the distal tube.

FIG. 6 is a flow diagram including method steps for attaching animplantable medical device to a delivery member. Referring to method1000 outlined in FIG. 6, in step 1010, the delivery member can beprovided. The delivery member can include a flexible distal hypotube, asdescribed herein. In step 1020, a first end of a loop wire can be passedthrough a proximal end of a first attachment slot of the distalhypotube. In step 1030, the first end of the loop wire can be pulledfrom the proximal end toward a distal end of the first attachment slot.As stated above, the distal end of the first attachment slot can have asmaller diameter than the proximal end.

In step 1040, the loop wire can be attached to the first attachmentslot. This attachment can be made in a number of ways, as describedherein. The loop wire can be welded to the first attachment slot. Inother examples, the loop wire can be affixed to the first attachmentslot via an epoxy. In other examples, the loop wire can include a knottied into the first end of the loop wire. The knot can be tied prior topulling the first end of the loop wire through the proximal end of thefirst attachment slot. In this case, the knot can be approximately thesame size as the diameter of the proximal end of the first attachmentslot. This can enable the knot to be fed through the proximal end butprohibit the knot from being pulled back through the distal end. Theknot can be tied after pulling the first end of the loop wire throughthe proximal end of the first attachment slot. The knot can be largerthan one or both of the proximal and the distal end of the firstattachment slot so that the loop wire cannot be pulled back through thefirst attachment slot. The first end of the loop wire can be attached atthe distal end of first attachment slot, or the first end of the loopwire can be attached at any other location in the first attachment slotthat is narrower than the proximal end (see, for example, FIG. 2E). Instep 1050 through step 1070, the method steps outlined above for steps1020 through 1040 can be repeated for a second attachment slot. Forexample, a second end of the loop wire can be positioned in a secondattachment slot similar to the process described above for the first endof the loop wire and the first attachment slot.

The descriptions contained herein are examples of embodiments of theinvention and are not intended in any way to limit the scope of theinvention. As described herein, the invention contemplates manyvariations and modifications of the delivery system, delivery member,and engagement system, including alternative configurations ofcomponents, alternative materials, alternative medical treatmentdevices, alternative means for deploying the medical treatment device,alternative geometries of individual components, alternative means forattaching component parts, etc. These modifications would be apparent tothose having ordinary skill in the art to which this invention relatesand are intended to be within the scope of the claims which follow.

What is claimed is:
 1. A delivery member for delivering an implantablemedical device to a target location of a body vessel, the deliverymember comprising: a proximal hypotube; a support coil section affixedto a distal end of the proximal hypotube; a distal hypotube comprising:a distal end shaped to receive the implantable medical device; a firstattachment slot extending from a lumen of the distal hypotube to anouter surface of the distal hypotube; and a second attachment slotextending from the lumen to the outer surface of the distal hypotube;and an engagement system movable to engage and deploy the implantablemedical device engaged at the distal end of the distal hypotube, theengagement system comprising: a loop wire extended through an opening inthe implantable medical device thereby engaging the engagement system tothe implantable medical device, a first end of the loop wire extendingat least partially through and attached to the first attachment slot viaa first weld or a first epoxy, and a second end of the loop wireextending at least partially through and attached to the secondattachment slot via a second weld or a second epoxy; and a pull wireextended through the lumen, engaged to the loop wire thereby engagingthe engagement system to the implantable medical device, and movable toretract proximally to disengage the loop wire to deploy the implantablemedical device.
 2. The delivery member of claim 1, wherein the firstattachment slot comprises a distal end and a proximal end, the proximalend of the first attachment slot having a first diameter and the distalend of the first attachment slot having a second diameter, the firstdiameter of the first attachment slot being larger than the seconddiameter of the first attachment slot, and wherein the second attachmentslot comprises a distal end and a proximal end, the proximal end of thesecond attachment slot having a first diameter and the distal end of thesecond attachment slot having a second diameter, the first diameter ofthe second attachment slot being larger than the second diameter of thesecond attachment slot.
 3. The delivery member of claim 1, wherein theloop wire comprises a metallic material.
 4. The delivery member of claim1, wherein the loop wire comprises a polymer material.
 5. The deliverymember of claim 1, wherein the distal hypotube further comprises aspiral cut along a longitudinal axis passing through the lumen.
 6. Thedelivery member of claim 5, wherein the first attachment slot isdisposed at a position on the distal hypotube opposite the secondattachment slot along a diameter line passing through the longitudinalaxis, and wherein the first attachment slot is positioned proximal tothe second attachment slot at a distance equal to one-half of a pitch ofthe spiral cut.
 7. The delivery member of claim 5, wherein the firstattachment slot is disposed at a first position equidistant from twoadjacent cuts of the spiral cut, and wherein the second attachment slotis disposed at a second position equidistant from two adjacent cuts ofthe spiral cut.
 8. The delivery member of claim 7, wherein the firstattachment slot and the second attachment slot are disposedperpendicular to the longitudinal axis.
 9. A distal hypotube for adelivery member, the distal hypotube comprising: a distal end shaped toreceive an implantable medical device; a lumen extending through thedistal hypotube; a first attachment slot extending from the lumen to anouter surface of the distal hypotube; a second attachment slot extendingfrom the lumen to the outer surface of the distal hypotube; a loop wireattached at a first end to the first attachment slot via a first weld ora first epoxy and attached at a second end to the second attachment slotvia a second weld or a second epoxy; and a spiral cut in the outersurface of the distal hypotube cut along a longitudinal axis passingthrough the lumen.
 10. The distal hypotube of claim 9, wherein the firstattachment slot comprises a distal end and a proximal end, the proximalend of the first attachment slot having a first diameter and the distalend of the first attachment slot having a second diameter, the firstdiameter of the first attachment slot being larger than the seconddiameter of the first attachment slot, and wherein the second attachmentslot comprises a distal end and a proximal end, the proximal end of thesecond attachment slot having a first diameter and the distal end of thesecond attachment slot having a second diameter, the first diameter ofthe second attachment slot being larger than the second diameter of thesecond attachment slot.
 11. The distal hypotube of claim 9, wherein theloop wire comprises a metallic material.
 12. The distal hypotube ofclaim 9, wherein the first attachment slot is disposed at a position onthe distal hypotube opposite the second attachment slot along a diameterline passing through the longitudinal axis, and wherein the firstattachment slot is positioned proximal to the second attachment slot ata distance equal to one-half of a pitch of the spiral cut.